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Nirmatrelvir-RitonavirMarketed under the brand name Paxlovid, data suggest that it significantly reduces the likelihood of hospitalization or death in COVID-19 patients, with a higher risk of severe illness.
For every 62 people treated with nirmatrelvir-ritonavir, the drug prevented 1 case of severe COVID-19.
Dr. Kevin Schwartz
“Many studies now support the efficacy of paxlobid for use in patients at risk of severe COVID-19. It’s important to have access to testing and to prescribers of paxlovid so that we can prevent serious consequences,” said lead author Kevin Schwartz, M.D., an infectious disease specialist with the Ontario Public Health Service and ICES. said he was a part-time scientist at Medscape Medical News.
In many areas, pharmacists can prescribe nirmatrelvir-ritonavir directly to patients, which could improve access to treatment, he added. “Prescribers must balance medication risks, including drug interactions, by considering individual patient risk factors, particularly older age, immunocompromised conditions, and other comorbidities. can be mitigated and it is important to evaluate all of these. Patience.”
the study published February 13th Journal of the Canadian Medical Association.
Important clinical benefit
Nirmatrelvir-ritonavir was shown to be effective in a randomized controlled trial conducted in 2021, but the trial included only unvaccinated patients and potentially significant drug interactions. Patients with the disease were excluded and were performed before the Omicron variant emerged, Schwartz said. However, in 2022, many patients who received this drug combination were vaccinated and had potential drug interactions. Additionally, a variant of Omicron was in circulation at the time.
Schwartz et al. conducted a population-based cohort study in Ontario that included adults with mild illness positive for COVID-19 by polymerase chain reaction test between April 4 and August 31, 2022. All-cause mortality and all-cause mortality at hospitalization or day 30 for COVID-19 were measured in patients not treated with this combination.
Of 177,545 patients, 8,876 (5%) were treated with nirmatrelvir-ritonavir and 168,669 (95%) were not treated. Most of the patients who received nirmatrelvir-ritonavir were older than 70 years old, had more than 3 doses of the COVID-19 vaccine, and had possible drug interactions.
Patients who received nirmatrelvir-ritonavir had a 2.1% risk of hospitalization or death, compared to a 3.7% risk for those who did not receive treatment. The weighted odds ratio (OR) for hospitalization or death within 30 days was 0.56 (P. < .001), the weighted OR for mortality only is 0.49 (P. < .001).
Overall, outcomes were similar across age, vaccination status, comorbidities, potential drug interactions, and risk status.
The research team found a weighted OR of 0.43 for hospitalization or death from April to June 2022 and a weighted OR of 0.67 from July to August 2022, with a possible decline in efficacy over time. I observed that A similar trend was observed for mortality alone.
Additionally, the researchers found that the number of treatments needed (NNT) to prevent one hospitalization or death was 62. They found considerable variability in absolute risk reduction. NNT ranged from 28 in the unvaccinated to 181 in those younger than her 70 years. Year.
“For example, approximately 30 unvaccinated patients need to be treated to prevent one severe case of COVID-19. It increases to about 80 in patients who have received it, and 180 in patients under the age of 70,” Schwartz said. “The prescriber should consider balancing the risks and benefits to the patient when prescribing paxlobid, balancing potential side effects and drug interactions, while having severe risk factors for her COVID-19. We should consider prescribing it to our patients.”
The researchers noted significant clinical benefits of using nilmatrelvir-ritonavir, but the benefits were less than those observed in a 2021 randomized controlled trial. It may be the result of differences in patient populations, underlying immunity, differences among circulating variants, or study design.
Effectiveness may vary
Additional studies need to look at differences by age and risk factors, write the study’s authors. obesityunderlying disease, and time since vaccination.
“It will be important to continue to monitor the efficacy of paxlobid,” Schwartz said. It may change over time.”
Based on the data sources used in this study, the authors should confirm whether patients are taking medications that may interact with nilmatrelvir-ritonavir, or potential medications during the prescribing process. We were unable to determine whether the interactions were moderated. In addition, Schwartz and colleagues continue to study the equity of nirmatrelvir-ritonavir prescribing in Ontario.
“The evidence suggests that some populations are less likely to have access to paxlovid, and we hope that we can improve this,” he said. We need to consider the social determinants of health when doing so.”
Needs continuous evaluation
Dr. Edward Mills
Commenting on the Medscape study, Dr. Edward Mills, Professor of Health Research Methods, Evidence, and Impact at McMaster University in Hamilton, Ontario, said: , among low-risk patients and in newer, less severe variants, failed to demonstrate a significant role for paxlovid. ”
Mills, who was not involved in the study, has been researching several COVID-19 treatments during the pandemic. Lopinavir-ritonavir (Kaletra), Ivermectin (stromectol), and Mornupiravir (Lagevrio). He pointed out that observational studies provide a weaker form of evidence for efficacy and may have false precision due to the large sample size of the control population.
“Continued evaluation of antiviral therapy is desperately needed,” he said. “Perhaps further randomized evaluation of Paxlovid will determine its continued usefulness.”
This study was funded by Public Health Ontario. Schwartz and Mills have not reported any related financial relationships.
CMJ. Published February 13, 2023. full text
Carolyn Crist is a health and medical journalist reporting on the latest research for Medscape, MDedge and WebMD.
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